Active Asteroids (citizen science project)

Active Asteroids is a NASA partner citizen science project that successfully discovered active asteroids, including main-belt comets, quasi-Hilda objects, and Jupiter family comets. The project is hosted on the Zooniverse platform and is funded by a NSF Graduate Research Fellowship Program. It uses images from the Dark Energy Camera (DECam) to search for tails around asteroids and other minor planets. The research team is led by Colin Orion Chandler.^[1][2][3] As of April 2024 about 8300 volunteers carried out 6.7 million classifications of 430 thousand images. At the time only 60 active asteroids were known and 16 new active objects were discovered by this project, significantly increasing the sample of known objects.^[2]

Active Asteroids

Type of site	Citizen science project
Available in	English
URL	www.zooniverse.org/projects/orionnau/active-asteroids
Commercial	No
Registration	Optional
Launched	31 August 2021; 3 years ago (2021-08-31)
Current status	Online

Pre-launch preparation

Before the team launched the project, the team gained experience with DECam and published three papers.^[4] These include detection of activity around previously known active asteroid (62412) 2000 SY178,^[5] revealing 6 years of avtivity on (6478) Gault^[6] and activity discovered on the centaur 2014 OG₃₉₂.^[7]

Discoveries

DECam image showing the activity on 282P, which was first identified by citizen scientists for this image.

The project uses a pipeline called HARVEST, which compares metadata from astronomical image archives with the data from the Minor Planet Center and produces images at positions of minor planets. It also excludes images with no detection or images that cannot detect asteroids.^[8] Since February 2024 the team also used a Convolutional Neural Network (CNN), called TailNet, to filter out bad images before they are shown to volunteers and to identify high-likely candidates. This CNN uses classification-labels made by the volunteers and is constantly improved with new classifications.^[9] One of the first discovery was made in September 2022, when the team published a paper describing that 282P/(323137) 2003 BM₈₀ showed sustained activity over 15 months in 2021-2022. Activity was previously reported in 2012-2013 and the team analysed the orbit, finding that it is an outbursting quasi-Hilda object.^[3] The object 2010 LH15 was discovered to have cometary activity from DECam images by the Active Asteroids project.^[10] A follow-up study did find activity in images of the Zwicky Transient Facility and showed that the object had a radius of 1.11±0.02 km. The study also showed that the activity was likely due to sublimation. The activity did onset at 1.86 astronomical units (AU), which is closer than other main-belt comets. The researchers find that sublimating volatiles must be buried deeper than on other active asteroids showing sublimation.^[11]

List of discoveries

Name	family	type of activity	year-month of disovery	Reference	Previous discovery of activity
2015 TC1	Jupiter-family comet		2022-01	[8][2]	no
2017 QN84	Jupiter-family comet		2022-01	[8][2]	no
282P	quasi-Hilda object (former Centaur or Jupiter-family comet)	volatile sublimation	2013-06/2022-09	[3]	yes, Bolin et al.[12]
2015 FW412	main-belt comet candidate	sublimation	2023-02	[13][2]	no
2015 VA108	main-belt comet candidate	volatile sublimation	2023-02	[14]	no
2009 DQ118	quasi-Hilda object (former Jupiter family comet or Centaur)	sublimation of volatile ices	2023-03	[15][16]	no
2010 LH15 (aka 2010 TJ175)	main-belt comet	likely sublimation[11]	2023-03	[10]	no
(588045) 2007 FZ18	main-belt comet candidate	two tails	2023-05	[17]	no
2018 CZ16	quasi-Hilda object	thermally driven activity indicative of water-ice sublimation	2023-05	[18]	no
P/2005 XR132[19]	Jupiter-family comet		2021-04/2023-07	[20][21]	yes, Cheng et al.[22]
2004 CV50	quasi-Hilda object		2023-11	[23]	no
(551023) 2012 UQ192	Jupiter-family Comet	recurrently active, sublimation	2023-12	[24][2]	no
2019 OE31	vacationing Centaur	volatile sublimation	2023-12	[25]	no
2008 QZ44	Jupiter-family comet		2023-12	[26]	no
2018 VL10	Jupiter-family comet (Mars crossing)		2023-12	[27]	no
2018 OR	Jupiter-family comet (Mars crossing)		2024-01	[28][2]	no
(410590) 2008 GB140	main-belt comet candidate		2024-02	TailNet identified activity[29]	no
2016 UU121	main-belt comet candidate		2024-02	TailNet identified activity[9]	no
2011 UG104	Jupiter-family comet		2024-05	TailNet identified activity[30]	no
2015 VP51	Jupiter-family comet	suspected sublimation	2024-09	TailNet filtered, identified by citizen scientists[31]	no
2010 MK43 (aka 2010 RA78)	Jupiter-family comet (former quasi-Hilda object)		2024-09	TailNet filtered, identified by citizen scientists[32]	no
(523822) 2012 DG61	Near-Earth Comet and Apollo asteroid	recurrently active, likely sublimation	2018-05/2025-01	TailNet identified activity[33]	previously observed by G. Borisov[33]

See also

other citizen science projects researching minor planets:

• The Daily Minor Planet Active
• Asteroid Zoo inactive
• Stardust@home
• Catalina Outer Solar System Survey inactive

other citizen science projects

• Zooniverse citizen science platform
• BOINC volunteer computing platform
• Planet Hunters: exoplanet discovery project
• Backyard Worlds: brown dwarf discovery project